Logistic regression analysis of factors associated with acquisition of syphilis
| Variable | Univariable | Multivariable | ||
| OR (95% CI) | P value | Adjusted OR (95% CI) | P value | |
| Age, per 10-year increase | 0.64 (0.61 to 0.66) | <0.001 | 0.71 (0.67 to 0.75) | <0.001 |
| HBsAg positivity | 0.87 (0.78 to 0.98) | <0.001 | 1.10 (0.95 to 1.26) | 0.20 |
| Male | 30.64 (12.71 to 73.83) | <0.001 | -* | – |
| MSM | 5.49 (4.35 to 6.93) | <0.001 | 1.75 (1.32 to 2.32) | <0.001 |
| History of syphilis | 5.78 (5.31 to 6.29) | <0.001 | 7.26 (6.48 to 8.14) | <0.001 |
| No follow-up RPR data in the preceding year(s) | 5.35 (3.84 to 7.45) | <0.001 | 3.02 (2.08 to 4.38) | <0.001 |
| Age group, years | ||||
| ≤30 | Reference | – | – | |
| 31–40 | 0.70 (0.63 to 0.77) | <0.001 | – | – |
| 41–50 | 0.51 (0.45 to 0.57) | <0.001 | – | – |
| >50 | 0.24 (0.21 to 0.27) | <0.001 | – | – |
*Male sex was not included in the multivariable model due to its high correlation with MSM status, to avoid multicollinearity.
HBsAg, hepatitis B surface antigen; MSM, men who have sex with men; RPR, rapid plasma regain.